1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
4 * Chen Liqin <liqin.chen@sunplusct.com>
5 * Lennox Wu <lennox.wu@sunplusct.com>
6 * Copyright (C) 2012 Regents of the University of California
9 #include <linux/compat.h>
10 #include <linux/signal.h>
11 #include <linux/uaccess.h>
12 #include <linux/syscalls.h>
13 #include <linux/resume_user_mode.h>
14 #include <linux/linkage.h>
15 #include <linux/entry-common.h>
17 #include <asm/ucontext.h>
19 #include <asm/signal.h>
20 #include <asm/signal32.h>
21 #include <asm/switch_to.h>
22 #include <asm/vector.h>
24 #include <asm/cacheflush.h>
26 unsigned long signal_minsigstksz __ro_after_init;
28 extern u32 __user_rt_sigreturn[2];
29 static size_t riscv_v_sc_size __ro_after_init;
37 u32 sigreturn_code[2];
42 static long restore_fp_state(struct pt_regs *regs,
43 union __riscv_fp_state __user *sc_fpregs)
46 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
48 err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state));
52 fstate_restore(current, regs);
56 static long save_fp_state(struct pt_regs *regs,
57 union __riscv_fp_state __user *sc_fpregs)
60 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
62 fstate_save(current, regs);
63 err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state));
67 #define save_fp_state(task, regs) (0)
68 #define restore_fp_state(task, regs) (0)
71 #ifdef CONFIG_RISCV_ISA_V
73 static long save_v_state(struct pt_regs *regs, void __user **sc_vec)
75 struct __riscv_ctx_hdr __user *hdr;
76 struct __sc_riscv_v_state __user *state;
81 /* Place state to the user's signal context space after the hdr */
82 state = (struct __sc_riscv_v_state __user *)(hdr + 1);
83 /* Point datap right after the end of __sc_riscv_v_state */
86 /* datap is designed to be 16 byte aligned for better performance */
87 WARN_ON(unlikely(!IS_ALIGNED((unsigned long)datap, 16)));
89 get_cpu_vector_context();
90 riscv_v_vstate_save(¤t->thread.vstate, regs);
91 put_cpu_vector_context();
93 /* Copy everything of vstate but datap. */
94 err = __copy_to_user(&state->v_state, ¤t->thread.vstate,
95 offsetof(struct __riscv_v_ext_state, datap));
96 /* Copy the pointer datap itself. */
97 err |= __put_user((__force void *)datap, &state->v_state.datap);
98 /* Copy the whole vector content to user space datap. */
99 err |= __copy_to_user(datap, current->thread.vstate.datap, riscv_v_vsize);
100 /* Copy magic to the user space after saving all vector conetext */
101 err |= __put_user(RISCV_V_MAGIC, &hdr->magic);
102 err |= __put_user(riscv_v_sc_size, &hdr->size);
106 /* Only progress the sv_vec if everything has done successfully */
107 *sc_vec += riscv_v_sc_size;
112 * Restore Vector extension context from the user's signal frame. This function
113 * assumes a valid extension header. So magic and size checking must be done by
116 static long __restore_v_state(struct pt_regs *regs, void __user *sc_vec)
119 struct __sc_riscv_v_state __user *state = sc_vec;
123 * Mark the vstate as clean prior performing the actual copy,
124 * to avoid getting the vstate incorrectly clobbered by the
125 * discarded vector state.
127 riscv_v_vstate_set_restore(current, regs);
129 /* Copy everything of __sc_riscv_v_state except datap. */
130 err = __copy_from_user(¤t->thread.vstate, &state->v_state,
131 offsetof(struct __riscv_v_ext_state, datap));
135 /* Copy the pointer datap itself. */
136 err = __get_user(datap, &state->v_state.datap);
140 * Copy the whole vector content from user space datap. Use
141 * copy_from_user to prevent information leak.
143 return copy_from_user(current->thread.vstate.datap, datap, riscv_v_vsize);
146 #define save_v_state(task, regs) (0)
147 #define __restore_v_state(task, regs) (0)
150 static long restore_sigcontext(struct pt_regs *regs,
151 struct sigcontext __user *sc)
153 void __user *sc_ext_ptr = &sc->sc_extdesc.hdr;
156 /* sc_regs is structured the same as the start of pt_regs */
157 err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
161 /* Restore the floating-point state. */
163 err = restore_fp_state(regs, &sc->sc_fpregs);
168 /* Check the reserved word before extensions parsing */
169 err = __get_user(rsvd, &sc->sc_extdesc.reserved);
177 struct __riscv_ctx_hdr __user *head = sc_ext_ptr;
179 err |= __get_user(magic, &head->magic);
180 err |= __get_user(size, &head->size);
184 sc_ext_ptr += sizeof(*head);
187 if (size != END_HDR_SIZE)
192 if (!has_vector() || !riscv_v_vstate_query(regs) ||
193 size != riscv_v_sc_size)
196 err = __restore_v_state(regs, sc_ext_ptr);
201 sc_ext_ptr = (void __user *)head + size;
206 static size_t get_rt_frame_size(bool cal_all)
208 struct rt_sigframe __user *frame;
210 size_t total_context_size = 0;
212 frame_size = sizeof(*frame);
215 if (cal_all || riscv_v_vstate_query(task_pt_regs(current)))
216 total_context_size += riscv_v_sc_size;
219 * Preserved a __riscv_ctx_hdr for END signal context header if an
220 * extension uses __riscv_extra_ext_header
222 if (total_context_size)
223 total_context_size += sizeof(struct __riscv_ctx_hdr);
225 frame_size += total_context_size;
227 frame_size = round_up(frame_size, 16);
231 SYSCALL_DEFINE0(rt_sigreturn)
233 struct pt_regs *regs = current_pt_regs();
234 struct rt_sigframe __user *frame;
235 struct task_struct *task;
237 size_t frame_size = get_rt_frame_size(false);
239 /* Always make any pending restarted system calls return -EINTR */
240 current->restart_block.fn = do_no_restart_syscall;
242 frame = (struct rt_sigframe __user *)regs->sp;
244 if (!access_ok(frame, frame_size))
247 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
250 set_current_blocked(&set);
252 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
255 if (restore_altstack(&frame->uc.uc_stack))
264 if (show_unhandled_signals) {
266 "%s[%d]: bad frame in %s: frame=%p pc=%p sp=%p\n",
267 task->comm, task_pid_nr(task), __func__,
268 frame, (void *)regs->epc, (void *)regs->sp);
274 static long setup_sigcontext(struct rt_sigframe __user *frame,
275 struct pt_regs *regs)
277 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
278 struct __riscv_ctx_hdr __user *sc_ext_ptr = &sc->sc_extdesc.hdr;
281 /* sc_regs is structured the same as the start of pt_regs */
282 err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs));
283 /* Save the floating-point state. */
285 err |= save_fp_state(regs, &sc->sc_fpregs);
286 /* Save the vector state. */
287 if (has_vector() && riscv_v_vstate_query(regs))
288 err |= save_v_state(regs, (void __user **)&sc_ext_ptr);
289 /* Write zero to fp-reserved space and check it on restore_sigcontext */
290 err |= __put_user(0, &sc->sc_extdesc.reserved);
291 /* And put END __riscv_ctx_hdr at the end. */
292 err |= __put_user(END_MAGIC, &sc_ext_ptr->magic);
293 err |= __put_user(END_HDR_SIZE, &sc_ext_ptr->size);
298 static inline void __user *get_sigframe(struct ksignal *ksig,
299 struct pt_regs *regs, size_t framesize)
302 /* Default to using normal stack */
306 * If we are on the alternate signal stack and would overflow it, don't.
307 * Return an always-bogus address instead so we will die with SIGSEGV.
309 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
310 return (void __user __force *)(-1UL);
312 /* This is the X/Open sanctioned signal stack switching. */
313 sp = sigsp(sp, ksig) - framesize;
315 /* Align the stack frame. */
318 return (void __user *)sp;
321 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
322 struct pt_regs *regs)
324 struct rt_sigframe __user *frame;
326 unsigned long __maybe_unused addr;
327 size_t frame_size = get_rt_frame_size(false);
329 frame = get_sigframe(ksig, regs, frame_size);
330 if (!access_ok(frame, frame_size))
333 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
335 /* Create the ucontext. */
336 err |= __put_user(0, &frame->uc.uc_flags);
337 err |= __put_user(NULL, &frame->uc.uc_link);
338 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
339 err |= setup_sigcontext(frame, regs);
340 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
344 /* Set up to return from userspace. */
346 regs->ra = (unsigned long)VDSO_SYMBOL(
347 current->mm->context.vdso, rt_sigreturn);
350 * For the nommu case we don't have a VDSO. Instead we push two
351 * instructions to call the rt_sigreturn syscall onto the user stack.
353 if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn,
354 sizeof(frame->sigreturn_code)))
357 addr = (unsigned long)&frame->sigreturn_code;
358 /* Make sure the two instructions are pushed to icache. */
359 flush_icache_range(addr, addr + sizeof(frame->sigreturn_code));
362 #endif /* CONFIG_MMU */
365 * Set up registers for signal handler.
366 * Registers that we don't modify keep the value they had from
367 * user-space at the time we took the signal.
368 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
369 * since some things rely on this (e.g. glibc's debug/segfault.c).
371 regs->epc = (unsigned long)ksig->ka.sa.sa_handler;
372 regs->sp = (unsigned long)frame;
373 regs->a0 = ksig->sig; /* a0: signal number */
374 regs->a1 = (unsigned long)(&frame->info); /* a1: siginfo pointer */
375 regs->a2 = (unsigned long)(&frame->uc); /* a2: ucontext pointer */
378 pr_info("SIG deliver (%s:%d): sig=%d pc=%p ra=%p sp=%p\n",
379 current->comm, task_pid_nr(current), ksig->sig,
380 (void *)regs->epc, (void *)regs->ra, frame);
386 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
388 sigset_t *oldset = sigmask_to_save();
391 rseq_signal_deliver(ksig, regs);
393 /* Set up the stack frame */
394 if (is_compat_task())
395 ret = compat_setup_rt_frame(ksig, oldset, regs);
397 ret = setup_rt_frame(ksig, oldset, regs);
399 signal_setup_done(ret, ksig, 0);
402 void arch_do_signal_or_restart(struct pt_regs *regs)
404 unsigned long continue_addr = 0, restart_addr = 0;
407 bool syscall = (regs->cause == EXC_SYSCALL);
409 /* If we were from a system call, check for system call restarting */
411 continue_addr = regs->epc;
412 restart_addr = continue_addr - 4;
415 /* Avoid additional syscall restarting via ret_from_exception */
419 * Prepare for system call restart. We do this here so that a
420 * debugger will see the already changed PC.
423 case -ERESTARTNOHAND:
425 case -ERESTARTNOINTR:
426 case -ERESTART_RESTARTBLOCK:
427 regs->a0 = regs->orig_a0;
428 regs->epc = restart_addr;
434 * Get the signal to deliver. When running under ptrace, at this point
435 * the debugger may change all of our registers.
437 if (get_signal(&ksig)) {
439 * Depending on the signal settings, we may need to revert the
440 * decision to restart the system call, but skip this if a
441 * debugger has chosen to restart at a different PC.
443 if (regs->epc == restart_addr &&
444 (retval == -ERESTARTNOHAND ||
445 retval == -ERESTART_RESTARTBLOCK ||
446 (retval == -ERESTARTSYS &&
447 !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
449 regs->epc = continue_addr;
452 /* Actually deliver the signal */
453 handle_signal(&ksig, regs);
458 * Handle restarting a different system call. As above, if a debugger
459 * has chosen to restart at a different PC, ignore the restart.
461 if (syscall && regs->epc == restart_addr && retval == -ERESTART_RESTARTBLOCK)
462 regs->a7 = __NR_restart_syscall;
465 * If there is no signal to deliver, we just put the saved
468 restore_saved_sigmask();
471 void init_rt_signal_env(void);
472 void __init init_rt_signal_env(void)
474 riscv_v_sc_size = sizeof(struct __riscv_ctx_hdr) +
475 sizeof(struct __sc_riscv_v_state) + riscv_v_vsize;
477 * Determine the stack space required for guaranteed signal delivery.
478 * The signal_minsigstksz will be populated into the AT_MINSIGSTKSZ entry
479 * in the auxiliary array at process startup.
481 signal_minsigstksz = get_rt_frame_size(true);
484 #ifdef CONFIG_DYNAMIC_SIGFRAME
485 bool sigaltstack_size_valid(size_t ss_size)
487 return ss_size > get_rt_frame_size(false);
489 #endif /* CONFIG_DYNAMIC_SIGFRAME */